Double shell tank fluid heater



April 22, 1969 M. SCHUCH I DOUBLE SHELL TANK FLUID HEATER Filed Dec. 13, 1967 INVENTOR. MARTIN SCHUCH BY ATTORNEY United States Patent "ice 3,439,666 DOUBLE SHELL TANK FLUID HEATER Martin Schuch, C1 Tower Trailer Park, Carteret, NJ. 07008 Filed Dec. 13, 1967, Ser. No. 690,337 Int. Cl. F24h 3/06; F24c 1/14; F24b 7/00 US. Cl. 126-110 4 Claims ABSTRACT OF THE DISCLOSURE A fluid heater is described having a hollow cylindrical outer shell and a hollow cylindrical inner shell annularly disposed so as to provide a narrow gas flow space between the two shells. The inner shell has inwardly-converging top and bottom portions which are connected with the corresponding outer shell portions by shell rings, which provide an upper inlet and lower outlet for fluid passing through the inner shell.

Plat arcuate pancake-type gas burners are placed in and on the lower juncture of the two shells, and an insulated cover is provided around the unit, there being a narrow annular air space between the inner surface of the cover and the outer shell. The cover extends beyond the upper juncture of the two shells, and a top connects the upper edges of the cover. A central opening in the tophouses a fluid blower which blows fluid, such as air, through the inner shell and through the annular space around the outer shell.

A cylindrical deflector having a diameter less than the inner shell inlet opening, is attached within and to the inner surface of the inner shell.

A flue connected to the upper portion of the outer shell and passing through the cover serves to discharge flue gas, while a duct connected to the lower portion of the outer shell serves to allow entry of the burners as well as the secondary air required. A circular plate is placed under the burners and in and over the lower junction of the shells to direct flow of secondary air from the duct to portions of the burner remote from the duct.

The cover is desirably extended below the lower junction of the shells, and a bottom is joined to the extending 3,439,666 Patented Apr. 22, 1969 latter serving as the entry means for the gas burners.

edges. -A central opening in the bottom permits heated fluid to pass out into a plenum chamber, for example, for heating purposes.

Background of the invention A large number of fluid heaters have been described and have appeared on the market. Most of them suffer from the fact that, if they are simple in construction, they are highly inefficient. And, if they are eflicient, they are quite complicated to make and consequently, are expensive.

In Patent 3,029,803, a double shell heater is disclosed. However the unit has a separate heating pot, and the air is blown at the side into the outer annular space only. The separate pot arrangement incurs the danger of mixing flue gas with the air, while the air feed method incurs considerable loss of heat due to the resistance involved.

The same is true of Patent No. 2,172,399, wherein air is blown from the side into an annular space. Both patents employ series flow of air, whereas a parallel flow of two air streams reduces considerably the resistance to flow.

There has been need for some time for a fluid heater which is simple to manufacture, and yet/is eflicient in heat output.

Summary of the invention According to the present invention, a highly eflicient unit is offered which is relatively simple to manufacture. It involves the use of two annularly-placed hollow shells, the inner shell having its ends inwardly converged, and

An outer insulated cover surrounds the outer shell in spaced relation, and a blower above the entry opening blows fluid through the inner shell. Also, a parallel air stream flows through the annular space between the cover and the outer shell, and the two heated air streams are united and led to the space to be heated. A bafile in the inner shell deflects the air toward the shell wall and thus improves heat transfer efliciency.

Such a unit is relatively simple to manufacture, yet it possesses extremely high efliciency.

Brief description of the drawings The invention will be more readily understood by reference to the accompanying drawing in which a preferred embodiment is described, and in which:

*FIGURE 1 depicts a cross-sectional vertical elevational view of a preferred embodiment.

FIGURE 2 presents a cross-sectional horizontal view taken along the plane of line 2-2 in FIGURE 1.

FIGURE 3 illustrates a similar view taken along the plane of line 33 in FIGURE 1, and

FIGURE 4 shows a similar view taken along the plane of line 4-4 in FIGURE 1.

The same numerals represent similar parts in the various figures.

Description of the preferred embodiment Referring to the drawing, numeral .10 represents generally the heater portion, while numeral 11 designates generally the insulated cover portion. The heater portion consists of a cylindrical outer metal shell 12. Disposed inside shell 12, in annular relation, is metal inner shell 13 which has its upper portion 14 and lower portion 15 turned inwardly. Both shells are connected at the top with a ring section 16, and at the bottom with a ring section 17. Between shells 12 and 13 is a narrow annular space 18 through which flue gases are designed to pass, discharging into flue 19, which is connected to the upper part of shell .12.

It -will be noted that the connections for the two shells provide an upper entrance opening 22, and a lower discharge opening 23 for air or other fluid forced through the center of shell 13. A cylindrical baffle 24 also is inserted inside shell 13, and is attached thereto by struts 25, and it serves to deflect the air stream toward the heated wall of shell 13.

The lower part of shell 12 is connected with duct 20, through which the gas lines 26 and 27 enter to supply gas to curved pancake type gas burners 21 and 21. The duct also serves as the entry for secondary air for the burners. A circular plate 28 laid over shell juncture 17 serves as a base for burners 21-21. The rear portion 29 of plate 28 is cut off to allow entry of secondary air from beneath plate 28 for the rear portions of the burners.

Attached to the outside of shell 12, in spaced relation therewith, by struts 30 is insulating cover 11, which consists of a layer 31 of magnesia, or other type of insulation, attached to metal shell 32. It will be observed that a narrow space 33 is thus provided between cover 11 and outer heater shell 12. Flue 19 and duct 20 project through cover shell 32, and the joints are sealed at 34 and 35, respectively.

Cover shell 32 is extended above the line of shell juncture 16, and a plate top 36 is connected to the upper edge of shell 32. Top 36 is provided with central opening 37,

and a collar 38 attached to said opening. Fan 39, driven by motor 40, is mounted in collar 38.

Cover shell 32 is extended below the line of shell juncture 17, and a plate 41 is connected to the lower edge of shell 32, to provide a bottom, which can rest on floor joists 42-4 3, for example. A flanged collar 44 can be provided to connect with an opening in a floor plenum chamber 45, for example, or other suitable duct for transferring heated air.

The heater is used as follows:

If the unit is to be used as an air heater, gas burners 2121 are ignited. This causes secondary air to flow through duct 20, and into the space between shells 12 and .13 and under plate 28. Enough air flows under plate 28 and through opening 29 to provide adequate secondary air for the portions of the burners farthest away from duct 20. The flue gases pass through annular space 18 and discharge through flue 19. This causes the heating up of shells 12 and 13.

Air blower 39 is started. This causes room air to be sucked through openings, as shown by the arrows, and to be blown through opening 22 where it is deflected by cylinder 24, so that it impinges on the inner surface of shell 13, and is discharged through opening 23 and out into plenum 45, or other space to be heated. The fan also blows air through annular space 33. This stream of air is heated by shell 12, and the thus-heated stream then joins the other heated stream, as they issue through collar 44.

It will be noted that the heater has an exceptionally high efliciency in view of the fact that both shell walls are employed for the heating operation, and a high velocity fluid flow provides an excellent film heat transfer coeflicient.

The unit may be employed to heat water, or other fluid, if desired, by making the necessary changes familiar to those skilled in the art.

I claim:

1. A fluid heater, of the type described, comprising:

a hollow cylindrical outer shell,

a hollow cylindrical inner shell disposed annularly within said outer shell in a manner so as to provide a narrow annular gas flow space therebetween, said inner shell having an inwardly-converging top portion and an inwardly-converging bottom portion,

a shell ring connecting member connecting the upper portions of said inner and outer shells, whereby a central inlet opening is provided for said inner shell,

a shellring connecting member connecting the lower portions of said inner and outer shells whereby a central discharge opening is provided for said inner shell, and serving as a repository for gas burners disposable thereon,

an insulated cover disposed in spaced relation over said outer shell and extending above said upper connected portions and below said lower connected portions,

a flue connected to the upper portion of said outer shell wall, and extending through said cover, and serving to discharge flue gases,

a duct connected to the lower portion of said outer shell wall, and extending through said cover, and serving as an entrance for fuel feed lines to said gas burners, and as an inlet for secondary air for said gas burners,

a top attached to the upper edges of said cover, and having means providing a central opening therein, and

fluid blowing means connected in said top opening and designed to blow fluid through said inner shell and around the outside of said outer shell in the annular space therearound.

2. A fluid heater, according to claim 1, in which a cylindrical gas deflector is disposed within and attached to the inner wall of said inner shell, said deflector having an external size smaller than said inner shell inlet opening.

3. A fluid heater, according to claim 1, in which a bottom is attached to the lower edges of said cover, and means are provided for a central opening therein for dis charge of heated fluid.

4. A fluid heater, according to claim 1, in which a flat circular plate is disposed within and on said lower junction of the inner and outer shells and under said burners and designed to direct a flow of secondary air from said duct to the burner portions remotely distanct from said duct.

References Cited UNITED STATES PATENTS 3,010,449 11/1961 Owen.

JAMES W. WESTHAVER, Primary Examiner.

U.'S. Cl. X.R. 

